By Alex Perez and Matthew Jaffe, ABC News
Law enforcement officials who have spent the past nine days searching for a pair of missing cousins in Iowa say some family members are not being completely cooperative and are now under close scrutiny.

"Law enforcement has not received total cooperation from all family and close friends. We feel there's someone out there that has pertinent information about the girls' whereabouts," FBI spokeswoman Sandy Breault said.

Elizabeth Collins and Lyric Cook, who are cousins, were last seen on July 13, riding their bikes near a lake in Evansdale, Iowa. Authorities reclassified the case as an abuduction Friday, and the FBI said they believe the girls are still alive. A $50,000 reward is now being offered for information that would lead to their being found.

Lyric's parents, Misty and Dan Morrissey, say they're taking legal advice, and will no longer allow police to interrogate them. Both have past convictions for felony drug offenses and spent time behind bars. Misty served four years in federal prison.

Some of their relatives acknowledge that the couple's troubled past could have played a role in the girls' disappearance.

In the past week investigators have questioned both Misty and Dan Morrisey several times. Brousseau said Dan Morrisey at one point left a police interview because he felt he was being treated like a suspect.

"I can see Dan becoming very defensive after he's being told, you know, 'You killed your daughter and niece. You know you did. We have proof. We have evidence that you did this,'" Brousseau said.

Brousseau said the Morrisseys, who are separated, have a violent past that even involves a restraining order.

"At one point Dan had assaulted Misty and that's where the no-contact order came into place," she said.

On Wednesday night investigators went to a nearby hotel where Misty and Dan Morrisey were staying, but Dan claimed he was tired and wanted to go to sleep. The following morning Misty took a urine analysis and a polygraph test. However, Brousseau said the pair had been advised by their attorney not to speak any further to police or the media or submit to any more polygraph tests.

Capt. Rick Abben, the spokesman for the Black Hawk County Sheriff's Office, said Thursday that their silence was not helpful to investigators.

"It's a distraction for us, and why they wish to do that, I don't know," Abben told reporters. "We're asking for 100 percent cooperation. Why they don't want to do that, I have no idea."

Late Thursday Misty and Dan Morrisey were spotted leaving the authorities' makeshift command center in Evansdale, with Misty in tears.

"They have no idea about anything," Misty yelled as she left the building.

"Back off," said Dan as reporters gathered around them.

With the search for the girls now more than a week old, family members want the focus to be on the two cousins, not Lyric's parents.

"Let's focus on Elizabeth and Lyric. Let's leave the past where it belongs," Ceilley urged Friday.

If one family member is getting roughed up, he said, "they're all getting roughed up."